Air compressor controller



8. E. SHAW AIR COMPRESSOR CONTROLLER Nov. 12, 1940.-

Filed April 4, 1938 2 Sheets-Sheet la/Fzyzzz Z02 ZZZ/OZZ Eff/212w Illlllllilfllllllr m mmm Nov. 12, 1940. I :B. E. SHAW 2,221,222

AIR COMPRESSOR CONTROLLER File'd April 4, 1938 2 Sheets-Sheet 2 60 59 a/ir'zz/ezzfar 43 $5 9. flair/0212f fazv.

Patented Nov. 12, 1940 UNITED STATES PATENT OFFICE AIR COMPRESSOR, CONTROILEB tion of Indiana Application April 4, 1938, Serial No. 199,905

Claims.

One of the objects of my present invention is to provide a comparatively simple, rugged and durable control device for heavy duty operation in the control of air compressor motors and the 6 like.

Another object is to provide a control device comprising a housing in which is mounted an automatic pressure responsive switch and a magnetic unloader for the air compressor, the parts being so arranged that compactness is secured and at the same time all adjustments are readily accessible when the housing is open.

A further object is to provide an air compressor switch having a. partition in the switch housing for dividing the current carrying contacts from the mechanical mechanismmf the housing, the partition being adjacent the top of the housing and having mounted thereon stationary contacts which face outwardly so that they are readily accessible for removing, cleaning and replacing purposes.

Another object is to provide a bridging memher having contacts for coaction with the stationary contacts which bridging member is also readily accessible for removal, cleaning and replacement, the structure being such that the bridging contacts float on contact carrying arms so that they are thereby suspended in a balanced manner on the arms.

Still another object is to provide shoulders on the arms against which the bridging members engage, spring means being used to cause such engagement and special washers coacting with T-head ends of the contact carrying arms to facilitate removal of the bridging members from the arms.

A further object is to provide a V-over roller connection between an actuating arm which is actuated by a pressure responsive diaphragm and a switch arm which carries the contact carrying arms, a differential spring being used to retain the spring and V-over roller connection in relative coaction and an adjusting screw for the diflerential spring being arranged so that an operating portion thereof is readily accessible for changing the tension of the spring.

A further object is to provide the actuating arm and the switch arm substantially spaced from each other so that between them a. range spring can be mounted, which has an adjusting screw also readily accessible, the V-over roller connection including a link mounted at one side of the housing so that there is a substantial space between the link and the other side of the housing to receive a magnetic unloader valve actuator.

Still a further object is to provide unloader mechanism including an unloadervalve mounted on the exterior of the housing and a magnetic unloader valve mechanism mounted on the interior thereof, this actuator being formed inexpensively of an enclosing pole of cast iron or the like with a solenoid mounted therein and a. comparatively heavy core movably mounted in the solenoid for actuating the unloader valve through the medium of a valve lever mounted to extend between the interior and the exterior of the housing.

As a further object of my invention I provide an air compressor controller in which all the parts are so designed and related to each other that they can be mounted in a minimum of space within a controller housing, whereby the overall dimensions of the controller may be kept small and none of the parts interfere with each other either during assembly or in operation after assembly.

Although the invention is susceptible of a variety of embodiments, it is unnecessary to fully describe and illustrate more than one in order to give. a full understanding of the inven tion both from its structural and functional standpcints. Accordingly, I have illustrated a preferred and desirable embodiment of the invention in the accompanying drawings forming a part of this specification and throughout the views of which like reference characters refer to the same parts.

Figure 1 is a side elevation oi an air compressor controller embodying my invention.

Figure 2 is an enlarged sectional yiew thereof on the line 2-2 of Figure 1 showing one of the contact bridging members removed.

Figure 3 is a sectional view on the line 3-4 of Figure 2.

Figure 4 is an exploded perspective view of the contact mechanism of the control switch in my control structure.

Figure 5 is a sectional view on the line 5-5 of Figure 3 showing a cross section through a magnetic unloader valve actuator which is omitted from the showing in Figure 3.

Figure 6 is an enlarged sectional view on the line 6--6 of Figure 1 showing the unloader valve and showing diagrammatically an air compressor system connected therewith.

Figure 7 is a sectional view on the line 1-1 of Figure 3. v

Figure 8 is a sectional view on the line H of Figure 3; and

Figure 9 is a sectional view on the line 9-8 of Fi ure 3 'to show the connection of a differential spring with its adjusting screw.

On the accompanying drawings I have used the reference character H to indicate generally a controller housing. The housing H comprises a back II, a bottom I! and a pair of sides I! and II. The housing also includes a cover member C having a top II and a front I. The cover member 0 is normally retained in position by screws ll which, after removal, permit the cover member to be removed thereby exposing both the top and front of the mechanism within the housing H.

A partition P is mounted within the housing H. This partition is made of insulating material and has a plurality of contact barriers ll extending upwardly therefrom. Between the barriers ll there is a series of stationary contacts is and another series of stationary contacts 20. As illustrated there are three contacts in each series, the controller being for a three-wire circuit. Obviously it can be provided for one or two wires or for four or more wires if desired.

The stationary contacts II are adapted to be bridged by bridging members II when the switch is in closed position. The members is, and II have appropriate contact points which are shown coacting with each other in Figure 3. The partition P is retained in Position at the back of the housing H by a pivot bolt 22 extending through perforated ears 28 thereof. At the front of the housing, screws 24 extend through the sides I! and I4 and into the partition.

Pivotally mounted on the pivot pin 22 is a switch arm 8. The switch arm 8 comprises a crow bar ll of insulating material and a pair of L-shaped side plates 20 and 21. The side plates 28 and 21 are secured to the ends of the bar 25 as by screws 20. The upstanding portions of the L-shaped arms 28 and 21 are provided with hubs 20 (see Figure 8) oscillatable on the pivot pin 22. The pivot pin is retained in position relative to the housing H by a nut 30.

The L-shaped arm 28 has an extension II toward the right from the bolt 22. A bracket II is riveted as at a to the inner face of the arm 2' (see Figure 3). The right hand ends of the extension 3| and the bracket 82 are provided with a pivot pin it and enlarged openings 35. A link 88 has a pin 31 extending through the enlarged openings II and is connected by a pair of links ll to the pivot pin 34. The links II have holes therein adjacent their ends for the pins It and 81. The links ll, together with the openings 3! and the pin 81, provide a lost motion connection by reason of the play of the pin 31 in the enlarged openings II, the purpose of which will hereinafter appear.

The arm 26 and the bracket 82 are provided with an arcuate slot 8! (formed with the axis of the bolt 2! as a center) which receives a stop pin lll projecting from the side ll of the housing H. The pin serves to limit the swinging movement of the switch arm 8 about the pivot bolt 22.

Mounted against a diaphragm plate ii on the bottom II of the housing H is a pressure diaphragm 42. It is retained in position on the bottom If by screws 44. A boss is provided on the diaphragm chamber 43 which is threaded to make connection with compressed air piping or tubing in the usual manner.

An actuating pin it rests against the diaphragm II and is retained thereagainst by a range spring 41. The spring 41 is interposed between washers ll and ll. The washer ll has at each side a pair of arms l0 eng n in reduced portions ll of a pin 52 (see Figure 5). The I pin 52 serves as a thrust connection between the pin 46 and the washer II.

The washer is is slidably mounted on a range adjusting screw it carried by a cross member 54 secured to the sides I! and ll of the housing H by screws '5. A nut It on the screw 83 may 'be rotated for adjusting the tension of the spring I. v

The ends of the pin l2 extend through a U- shaped actuating arm I]. The arm is pivoted onapin llwhichinturnissupportedbya bracket II. An L-shaped extension I is riveted to the cross member of the U-shaped actuating arm l1 and is formed to provide a bifurcated portion in which a roller ll is mounted. a The roller II has its bore receiving a pin I! carried by the actuating arm extension ll. '.I"he roller is provided with a pair of side flanges ThelinkilhssaV-shapedendfladapted to coast with the roller I to provide a "V-over roller" type of connection between the actuating arm and the switch arm. For retaining the parts of the v-over roller connection in coaction with each other. I provide a differential spring ll. One end of the spring II is connected toaperforatedearliofthelinkllwhilethe other end is connected to,a nut I? (see Figure 9) into which a differential adjusting screw II is threaded. The screw ll extends rotatably through a perforated ear ll of the cross bracket I and has an operating portion thereon consisting of a head II. lb retain the head II in any position to which it is rotated. a U-shaped spring ll engages opposite sides thereof (as 40 shown in Figure 7) and the spring has a clip portion 12 as shown in Figure 3 extending back of the ear to retain the spring in position and against rotation relative to the ear H.

The bridging members II are mounted on the 5 switch arm cross bar 2! in the following described manner: Contact carrying arms 18 extend upwardly from the bar fl and are electrically insulated from each other by the bar. Thearmsll asshowninl 'lgureiareprovidedso with shoulders H and with T-heads II. The contact members 2! are provided with slots 10 which loosely receive the arms II above the shoulders ll. Springs 11 are mounted on the arms I! after the bridging members 24 are positioned thereon and after washers I8 are posi- Itaieoned on the arms against the bridging mem- For retaining the springs 11 in position and backing them up so that they tend to retain 00 the bridging members 2| against the shoulders II, I provide spring washers I. These washers are provided with slots I and depressions ll transversely of the slots. The washers II are associated with the T-heads is by permitting the T-heads to be extended through the slots 80 and then rotating the washers a quarter turn so that the springs urge them outwardly when the depressions ll coact with the T-heads as shown in Figure 2. Thus the washers II are readily removable whereupon the spring 11 and the washer II can also be removed from the contact carrying arm 13. This permits removal of the bridging members 2| so that their contact points can be readily cleaned and so that 7' ing parts, as illustrated in. Figure 6.

heavy core,.member is necessary in order to efthe contact points of the stationary contacts [8 and are exposed 'ior ready cleaning. *Onthe side ll .oi the "bracket '82..

housing H, I provide a An unloader valve V is mounted on'this bracket and may comprise the follow- A valve body 83 is secured to the bracket 82 as by lock nuts 84. An air. inlet 85 is provided in the body 88 and an unloader chamber connection is provided by a passageway. 88. Communication between the passageways 85 and 88 may be controlled by a valve member 81 whilecommunication between the passageway 88 and a passageway 88 which communicates with atmosphere is provided by a valve member 89-. The valve member 88 has a resiliently mounted operating pin 80.

The valve lever Si is pivoted on a pivot pin 82. The pivot pin 82 is carried by a bracket 93 extending from the side ll of the housing H adjacent an opening 84 therein. The valve lever extends through this opening and has a short end positioned under the operating pin 90 as shown in Figure 8.

A magnetic unloader valve actuator is provided in the form of a pole 85, a solenoid 96 and a core 81. The pole 95 is of the enclosing type or, in other words, substantially surrounds the solenoid 88. It is preferably made of soft cast iron and has a stop member 98 secured to the top thereof by a cap screw 88 as shown in Figure 8.

A washer I8!) is secured to the lower end of the enclosing pole 85 for retaining the core 81 against 88 dropping out of the bore of the solenoid. The

core 81 is adapted to engage the long end oi the valve lever 8|.

As shown diagrammatically in Figure 6 the unloader valve V is adapted to be connected in an air compressor system in which there is a tank T and an air compressor AC. The compressor AC supplies compressed air to the tank and the tank is connected with the passageway 85 of the valve V. Normally the valve is in the position shown in Figure 6 when the system is in operation, as the solenoid 88 is energized when the motor circuit is energized and the long end 01' the valve lever 8| is thereby held raised by a spring 81a in the valve V. When the circuit of the switch is open, both the air compressor and the solenoid 88 are de-energized, thus permitting the valve member 89 to close and the valve member 81 to open. Thereupon air flows from the passageway 88 thru piping Hll to an unloader chamber I02 of the air compressor for holding the intake valve I03 thereof of! its seat. This unloads the air compressor by permitting it to breathe" through the intake valve while the compressor is getting up to speed. As soon as the air compressor is started, however the solenoid 88 is energized for closing the valve 81 and opening the valve 88 so that air in the unloader chamber I02 gradually escapes to atmosphere and thereby permits normal functioning of the intake valve by the time the air compressor has attained its normal speed.

The design of my air compressor switch has solved several problems. In order to provide a powerful actuating device for the unloader valve particularly when a three-way valve, as shown in Figure 6, is used, and yet have a structure which can be economically made, a relatively heavy and large pole member 95 of cast iron has been provided and a relatively heavy core member 81 has also been provided. This feet positive, opening of the valve 81 against tank pressure and such opening is facilitated by the leverage of the lever 9|. When a heavy core member is provided, obviously a strong pull must be exerted thereon to lift it. By providing a substantially closed path for the magnetic flux oi the solenoid 98 through the pole member 95 as I have it shaped and by providing the stop extension 98, I am able to exert considerable pull on the core 91 when the solenoid is energized without having to go to expensive laminated construction.

By arranging the switch mechanism in the housing H as disclosed with the actuating arm 51 adjacent the bottom thereof, the link 86 adjacent one side and the partition P and the switch arm S adjacent the top, I provide considerable space within the housing inwhich the relatively large magnetic unloader valve actuator can be mounted. At the same time the parts have been so designed that ready access can be had to the contacts for cleaning them and the diiierential and range adjustment screws can be readily adjusted when the cover member C has been removed from the housing. The construction shown in Figure 4 facilitates removal of the bridging members 2| so that all the contacts of the switch are thereby accessible for cleaning.

Some changes may be made in the construction and arrangement of the parts of my controller without departing from the real spirit and purpose of my invention, and it is my in tention to cover by my cleaims, such modified forms of structure or use of mechanical equivalents as may be reasonably included within their scope.

I claim as my invention:

1. In an air compressor switch, a switch housing, a partition therein spanning the distance between two opposite walls of said housing and serving as a spacer therebetween, a switch arm mounted for swinging movement toward and away from the bottom of said partition and having, contact carrying arms extending through an opening in the partition, stationary contacts mounted on the top of said partition, bridging members having contacts for coaction with said stationary contacts and carried by said contact carrying arms, said contact carrying arms having shoulders for said bridging members to normally rest against, resilient means constraining said bridging members to rest against said shoulders, means for limiting the movement of said switch arm to a position with said shoulders spaced from said bridging members when the switch arm is in closed circuit position, and air pressure responsive means for swinging said switch arm toward and away from'said parti- 2. In an air compressor switch, a switch housing, a switch arm mounted for movement therein and having contact carrying arms, stationary contacts mounted in said housing, bridging members having contacts for coaction with said stationary contacts and carried by said contact carrying arms, resilient means constraining said bridging members to engage said stationary contacts when the switch arm is in closed circuit position, said resilient means comprising springs encircling the contact carrying arms and washers for retaining said springs in position, said contact carrying arms comprising fiat blades having T-heads and side lugs spaced below said heads. said washers having slots through which said r-heads may be extended and having depressions transversely of said slots to receive said T-heads whereby said washers may be associated with the contact carrying arms by extension or the T-heads through said slots and rotation oi the washers thereafter for said depressions to coact with said r-heads, said washers serving as back stops ior said springs, said springs. in the open circuit position of said switch arm, engaging said bri ging members with said side lugs 01 said contact carrying arms. said bridging mem-. bers being slotted and loosely receiving said contact carrying arms so that after removal of said is washers and springs, said bridging members may be removed mm said contact carrying arms to permit unobstructed access to said stationary contacts and air pressure responsive means tor swinging said switch arm toward and away from said partition.

3. In a control switch. a cuboid switch housing comprising tour walls and a cover providing two walls, a partition in said housing, said partition connecting two of said four walls together I and thereby retaining proper spacing between them. a switch arm mounted tor swinging movement toward and away from said partition and having a contact carrying arm extending through an opening in the partition, stationary contacts mounted on said'partition, a bridging member having contacts for coaction therewith and carried by said contact carrying arm, said contact carrying arm having an integral shoulder for said bridging member to normally rest against.

U resilient means constraining said bridging memher to rest against said shoulder. means for limiting the movement of said switch arm to a position with said shoulder spaced irom said bridging member when the switch arm is in closed so circuit position, and condition responsive means for swinging said switch arm toward'and away from said partition.

4. In an air compressor switch, a substantially rectangular housing. a switch arm therein adja- 0 cent the top thereof. contacts operatively connected with said switch arm and means tor spar ating said switch arm comprising a pressure responsive element on the bottom of said honing adjacent the front thereoi. and an actuating arm s extending along one horisontal corner of said housing for actuation by said pressure responsive element. a link extending along one oi the vertical corners of said housing. connected with said switch arm and having a V-over roller connae- 10 tion with said actuating arm. a diflerential swing retaining said v-over roller connection in cooperating relationship and extending at substantiallyrightanglesiromsaidlinkalongonesids otsaidhousingtctheirontthereohadiilm tial adjuster screw for adjusting the tension at said diiierential spring, a range lpring tor said actuating arm and extending substantially parallel to said link and adjacent said front of mid housing. and a range djuster screw theretor, I said diflerential and range adjuster screws having operating portions adjacent said front 0! said housing.

5. In an air compressor switch. a substantially rectangular housing. a switch arm therein adja- Q cent the top thereof, contacts operatively cmnectedwithsaidswitcharmandmsansioroperating said switch arm comprising a M responsive element on the bottom of said hotning and an actuating arm adjacent one side of said housing for actuation by said element. a link connected with said switch arm. extending alcmg said side of said housing and having a V-over roller connection with said actuating arm. a diti'erential spring retaining said v-over roller connection in coacting relationship, a diflerential adjuster screw for adjusting the tension of said .diflerential spring, a range spring for said actuating arm. a range adjuster screw therefor, said actuating arm having its V-over roller connec- 0 tion at one of the vertical corners oi said housing,saidlinkbeingadjacentandextendingalong said corner of said housing.

' BURTON Ii. SHAW. 

